in the classic brush construction (German AUS No. 1114463), the bristle bunches are fastened by pressing them into openings of the brush head member. The bristles are bent at 180.degree. prior to the pressing in operation and have a thin wire around them at the bent area. Bunches which are prepared in this manner are then pressed into the holes of the brush head member. The holes were earlier prepared by a drilling operation.
Machines are used for these operations, with which brush head members can be rotated into any desired positions, so that openings of any desired direction can be provided in the brush head member and pushingin elements for pressing in of the bunches can each be aligned to the axis of the receiving opening. A machine of this type is illustrated in the aforesaid German AUS No. 1114463, in which a turret rotates about a vertical axis. Such machines can, however, also be built with turrets which are rotatable about horizontal axes. Any type of brush shapes can be manufactured with these machines, wherein the brush head can also have a curved bristle-lined surface and the bristle bunches can have any desired directions, so that any desired angular dispersion can be manufactured. This is an important advantage because for many brushes a lateral projection of the bristles beyond the lateral edges of the brush head is desired so that the bristles will reach into corners, which would otherwise be prevented by the brush head contacting a wall surface. At this point it is remarked that the term brushes is not only to include brushes in the more narrow sense, namely relatively short-bristle articles with relatively stiff bristles, but also other articles, as for example brooms and whisk brooms.
The classic brush construction requires a brush head, which is sufficiently thick that the openings which are needed for pressing in of the bunches can be manufactured with the necessary depth, for which reason the brush heads are relatively thick parts. The areas in which the bristles engage the holes are not accessible. Germs and other contaminants can settle therein, which raises doubt with respect to hygiene, for example, where brushes are to be used for creating conditions as sterile as possible, for example in hospitals.
Brushes have also become known lately in which bristles consisting of a thermoplastic plastic material are welded to a brush head which also consists of a thermoplastic material. For the manufacture of such brushes, machines are used (see for example U.S. Pat. No. 3,604,043) which have a bristle magazine, in which bristles, which are cut to length, are stacked. Holes are provided in the magazine wall for receiving small tubes therein, which small tubes are mounted on a bunch holder and are filled with bristles when inserted into the magazine. The ends of the bristle bunches are then pressed against a heating plate and are warmed up until the bristles melt together. The brush head which consists of thermoplastic material is also melted at each desired fastening point and several bristle bunches are simultaneously welded to the brush head. The brush head has a flat bristle-lined surface.
Such brushes have the advantage that openings for engagement by the bristle bunches are not required, so that the brush head can be constructed relatively thin. Also depressions do not exist for the collection of contaminants. It is disadvantageous that machines do not exist which permit the manufacture of brushes of any desired shape, thus for example of brushes with a fanned bristle bunch arrangement, in which the angle of inclination differs from bristle bunch to bristle bunch.
The basic purpose of the invention is to provide a machine which permits a manufacture of brushes with bristle bunches which are welded to the brush head, which have just like in the classic brush construction any desired shape, wherein also any desired direction of the bristle bunches is possible.
The attainment of this purpose is based on a conventional (German Pat. No. 1114463) machine for the manufacture of brushes wherein at least one brush head mounting structure for brush heads is provided, which mounting structure is pivotal about two axes, and furthermore is longitudinally movable. The machine includes a bristle bunch holder for gripping of bristle bunches and which is movable for supplying the bristle bunch to a brush head. Such a machine is characterized inventively by arranging at least two heating elements with contact heating surfaces thereon between the bunch holder and the brush head mounting structure, which are provided on a movable heating-element carrier movable between an engaging position in which one heating surface is adjacent to the brush head and the other adjacent to the bunch holder, and a rest position, which lies outside of the range of movement of the bunch holder.
The brush member can be swung with such a machine just like with the classic brush manufacturing machines into any desired position. The brush head is now melted at the desired location with a heating element, while at the same time the other heating element melts a bristle bunch at its end. After swinging out of the heating elements from the area between the brush head and bristle bunch, the bristle bunch is guided to the brush head and is welded to same. During the creation of the contact between the bristle bunch and the brush head, the places which had been warmed up earlier with the heating elements are still in a tacky condition. After welding of the bristle bunch to the brush head, the bunch holder returns into its initial position, the brush head is swung into a new position and the heating elements are swung between the bristle bunch holder and the brush head, after which the described operations are repeated.
The invention brings about the advantage that it is now also possible to manufacture brushes with bristle bunches weldably secured thereto in any desired overall shape so that the advantages of classic brushes, namely their advantageous overall shapes are related to the advantages of brushes with bristles welded to the brush head, namely thin brush heads can be used and the more advantageous hygienically maintainable brushes are obtained. Also the process of drilling bristle-fastening holes is no longer necessary.
It is preferable to arrange the two heating elements on one heating piece, because then only one movement device is needed for the heating elements. However, embodiments are also part of the invention in which two separate heating elements with separate movement devices are used. The movement devices for the heating-element carrier can be pivotally mounted on a frame for the aforesaid movement, even though other movement devices can also be used. Thus the movement and pulling back of the heating-element carrier could also take place along a rectilinear guideway.
It is also an object of this invention to provide an arrangement of a bristle magazine from which the bristles are inserted into small tubes, as this is actually known from the state of the art. However, it is also possible to weld bristles which are bent at 180.degree. to a brush head. The removal of the bristles from the magazine can, as is actually known, occur by introducing the small tube into the magazine. However, it is also possible according to the invention to secure a small tube on the magazine, into which small tube bristles are pushed by a plunger.
Various other embodiments are possible for the invention. One embodiment includes a movably arranged bristle magazine. Of course, not all objectives need to be simultaneously realized in this embodiment. For example, in place of cam plate gearing driving the magazine carriage for movement, it would also be possible to use fluid pressure power cylinders for the movement thereof. The use of a magazine having several compartments provides a means of selection, namely, permitting the use of several bristle types on one brush, for example hard and soft bristles or bristles of differing colors. With this type of magazine, it is also possible to provide bristle bunches of differing thicknesses. The size of the bunch is determined by the plunger diameter and the small tube diameter. The plunger and the small tube can be easily exchanged.
A further embodiment in which bristles can be processed from a spool is also possible. Such an embodiment has naturally no bristle magazine with bristles stored therein and which are cut to length. This embodiment has the advantage that the operation of cutting to length away from the machine is omitted.
The parallel arrangement of several brush head mounting structures has the advantage that the output of the machine is increased, namely, by a factor which equals the number of the parallel arranged brush head mounting structures, etc. It must be remarked here, that the heating up and welding of a bristle bunch to a brush head takes more time than pushing a bristle bunch into a hole. This disadvantage is partly cancelled by the time it takes to drill the holes in the brush head, which step is deleted, however, the time for the drilling of a hole and the pushing in of a bristle bunch together is still shorter than the time for heating up and welding of a bristle bunch to the brush head. The output of an inventive machine can, however, be achieved in a desired degree by the described parallel arrangement of brush heads and bristle bunch holders.
The method of operation has the advantage that the heated-up locations on the brush head and on the bristle bunch can contact one another in as short a time as possible after the heating-up procedure. However, due to the material character a certain phase shifting between the heating up of the brush head and the heating up of the bristle bunch can also be preferable. It is also possible to use different time intervals for contact between the one heating element and the brush head and for contact between the other heating element and the bristle bunch.